1. Field of the Invention
The present invention relates to a spring clip that couples a thermal element to an integrated circuit or integrated circuit package.
2. Background Information
Integrated circuits are assembled into packages that are soldered to printed circuit boards. The integrated circuits generate heat which must be removed to insure that the junction temperatures of the circuits operate below threshold levels. The heat generated by each integrated circuit primarily flows through the package. The package is typically constructed from a dielectric material which has a relatively low coefficient of thermal conductivity. The low thermal coefficient increases the temperature drop across the package and the junction temperature of the circuit.
Some packages contain a metal lid that reduces the thermal impedance between the integrated circuit and the ambient. A heat sink may be coupled to the metal lid to further improve the thermal efficiency of the assembly.
The surface roughness and a lack of co-planarity between the metal lid and the heat sink may create air gaps within the metal lid/heat sink interface. The air gaps increase the thermal impedance between the metal lid and the heat sink. The increase in thermal impedance may raise the junction temperature of the integrated circuit.
Some assemblies utilize a fastener such as a clip or a screw that pulls the heat sink into the metal lid. The pull force of the fastener decreases the thermal impedance of the metal lid/heat sink interface. Variations in the height of the integrated circuit package due to manufacturing tolerances may change the pull force of the fastener. The tolerances may create an undesirable reduction in the pull force and an increase in the thermal impedance of the metal lid/heat sink interface. It would be desirable to provide a clamping fastener for an electronic assembly which accommodates tolerances in the assembly.
One embodiment of the present invention is an electronic cartridge that includes a spring clip which attaches a thermal element to an integrated circuit or an integrated circuit package. The integrated circuit/package is mounted to a substrate. The cartridge may have a pin that extends from the thermal element and through the substrate. The spring clip is attached to the pin of the thermal element.